Inorganic and/or organic cellulose swelling agents used in conjunction with cross-linking agents in fabric modification process



United States Patent 3,533,728 INORGANIC AND/ OR ORGANIC CELLULOSE SWELLING AGENTS USED IN CONJUNCTION WITH CROSS-LINKING AGENTS IN FABRIC MODIFICATION PROCESS Fred B. Shippee, Ho-Ho-Kus, N..l., and Domenick Donald Gagliardi, East Greenwich, R.I., assignors to Gagliardi Research Corporation, East Greenwich, R.I., a corporation of Rhode Island No Drawing. Continuation-impart of applications Ser. No. 332,799, Dec. 23, 1963, and Ser. No. 547,751, May 5, 1966. This application July 28, 1967, Ser. No. 656,653

Int. Cl. D06m 13/44, 13/48, 13/12 U.S. Cl. 8-116.2 10 Claims ABSTRACT OF THE DISCLOSURE Cellulosic fabrics and garments are given wash-wear properties without serious loss of tensile strength, tear strength and flex abrasion resistance by preforming crosslinking and similar wrinkle proofing treatments with aqueous solutions of organic crease-proofing agents in the presence of aprotic organic cellulodilators. Additional presence of inorganic cellulodilators produces still further improvements in fabric whiteness and abrasion resistance, e.g., cross-linking of cotton with a catalyzed aqueous solution of dimethylol ethylene urea containing dimethyl sulfoxide and zirconium chlorhydroxide.

CROSS-REFERENCE TO RELATED APPLICATIONS Reference is made in accordance with the provisions of 3S U.S.C. 120 to application Ser No. 332,799, filed Dec. 23, 1963 (now abandoned) and copending application Ser. No. 547,751, filed May 5, 1966 (now abandoned), of which the present application is a continuation-in-part.

BACKGROUND OF THE INVENTION Field of the invention The art of treating cellulosic fabrics with chemical reagents to improve wrinkle resistance is highly developed. Actually, such procedures are widely practiced today on a commercial scale and cotton fabrics that have been treated with cross-linking agents to improve wrinkle resisting properties are readily available to any interested buyer. Fabrics of this type are widely used in the making of wearing apparel, for example, mens shirts and womens dresses. The popular term for this type of material is wash-wear fabric.

Procedures for finishing cellulosic fabrics with chemical agents to improve crease resistance can be divided into several broad, separate categories, e.g., those which utilize aqueous solutions of treating agents, and, contrastingly, those which may be used under anhydrous conditions, usually employing inert or non-reactive solvents. The present invention relates to the category of fabric treatments which fall in the first class, namely, those which are aqueous solutions.

Crease-proofing agents applied to cellulosic fabrics from aqueous solutions function basically in one of two ways. The agent may be capable of thermosetting into a resinous material with the resulting crease resistance of the treated fabric being due entirely to internal crosslinking of the treating agent while mechanically bonding to the fibers. Theoretically, since reaction between the treating agent and the fibers is unnecessary for the anticreasing effect, such agents could be used for the processing of fabric material made of any type fiber. Another basic type of water-soluble, crease-proofing agents are materials which by themselves are not capable of Patented Oct. 13, 1970 "ice thermosetting or forming resinous reaction products, but depend, for their anti-creasing properties, upon reaction with cellulose fibers of the treated fabric. Obviously, such agents would be restricted in their use to the treatment of fabrics containing cellulosic fibers or fibers of other substances which would be capable of reacting with the treating agent to effect a cross-linking or some other type of chemical reaction which would produce the crease resistance in the treated fabric.

Many treating agents which have been suggested and some of which are commercially used today in the processing of cotton fabrics into wash and wear materials do not fit strictly into either of these two types of materials. Thus, the ultimate crease resistant properties of the treated fabrics appear to be due to not only reaction between the treating agent and the cellulose, but also cross-linking between the treating agent itself resulting in a substantial amount of thermoset resin formation in conjunction with reaction with hydroxyl groups of the cellulose fibers. The present invention concerns improvements in the finishing of cellulosic fabrics within the total spectrum of anti-creasing agents that fall in the group of those which are nitrogemcontaining, water-soluble and, at least to some extent, cellulose-reactive. This encompasses the majority of nitrogen-containing fabric treating agents used on a commercial scale at the present time for imparting crease resistance to cellulosic fabrics.

By the term water-soluble as used herein, is meant a material which can be dissolved to an extent of at least 1% by weight in water at 20 C.

Description of the prior art The treatment of cotton and other cellulosic fabrics with crease-proofing agents is well described in patents and technical literature. Early in the development of the art, reaction products of urea with formaldehyde were employed and later used with modifications (see U.S. 2,808,341). Water-soluble reaction products of formaldehyde with melamine have been developed as oifering certain advantages (see U.S. 2,819,179). These materials had the disadvantage, however, of rendering the treated fabric susceptible to degradation upon bleaching with chlorine containing bleaching agents followed by heating.

This led to the development of the use of formaldehyde condensation products of cyclic ureas which had improved characteristics as regards chlorine degradation, for example, ethylene urea-formaldehyde reaction products (U.S. 2,898,238), propylene urea-formaldehyde products (U.S. 2,899,263), bis-hydroxyethylene ureaformaldehyde reaction products (U.S. 3,029,164) and related amino-aldehyde condensation products. Other nitrogen-containing, water-soluble, condensation products of aldehydes with amino compounds have been used for the treatment of fabrics in order to create anti-creasing or wrinkle resistance in the fabrics, such as tetrahydros-triazones (U.S. 2,950,552), aminotriazines (see U.S. 2,191,362) and the like. The aqueous systems used for treating fibers and fabrics usually include catalysts for the curing or cross-linking reaction. Some of the prior used catalysts may also function as swelling agents for the fibers, e.g., zinc chloride (see U.S. 3,181,927).

Most of the above mentioned methods impart dry crease resistance to cotton fabrics with an accompanying strength loss of 25 to 35% and this has been one of the major problems in the use of this type of finishing agent for obtaining crease resistance in cellulosic fabrics. Of even more concern, is the fact that strength loss of 50% or greater usually results when these agents are used with cotton at a sufiiciently high level to impart good wet-crease recovery to the fabrics. Investigations seeking an explanation for this effect have been made by exploring chemical structural changes that may take place in the cellulose molecules during the crease-proofing treatment (see D. D. Gagliardi et al., Textile Research Journal, vol. 37, No. 2, February 1967, pp. 118-128).

High degrees of Wet-crease recovery can be achieved with other classes of cellulose cross-linking agents and some of these are capable of imparting, under properly applied conditions, dry-crease recovery as well as wetcrease recovery. For example, cyanoethylation under controlled conditions may be used for this purpose. Also, formaldehyde in relatively high concentrations applied under acid conditions has been used for cross-linking cellulose to achieve wrinkle resistance, while materials applied under alkaline conditions for this purpose include divinyl sulfone or its derivatives (U.S. 2,524,399), or epichlorohydrin or its derivatives (US. 2,985,501). The treatment of cellulose with these latter types of anti-crease agents inherently result in relatively high tensile strength losses in the fabric, degradation of color, and generally the dry-crease resistance characteristics of the fabrics are not good. It is also possible to treat cellulose or cellulose-containing fabrics with other cross-linking agents which will produce various eflects in the fabric without, however, appreciably effecting the crease resistant qualities of the fabric. For example, cellulose fabrics may be treated with diisocyanates to make them water-repellent and improve wet and dry strength (see US. 2,339,913). Such treatments must be carried out under non-aqueous conditions and various anhydrous solvent systems have been suggested for this purpose, for example, dimethyl sulfoxide (see US. 3,007,763).

Although, as is apparent from the above discussion, the treatment of cellulosic fabrics, and cotton textiles in particular, to improve anti-creasing or wrinkle resisting properties is a highly developed art, there is still much room for improvement. There is a need for methods which can be utilized in a commercially feasible manner to treat cotton textiles or other cellulosic fabrics to impart to the fabrics high level of both wet and dry wrinkle resistance without, at the same time, creating loss in tensile strength and without adversely effecting other desirable properties of the treated fabric. A total evaluation of the effect of a particular treatment as applied to cellulosic or other fibers or fabrics may require, in addition to (A) tensile strength, consideration of (B) toughness index, (C) abrasion resistance, and (D) tear strength.

OBJECTS A principal object of this invention is the provision of new processes for improving the wet and dry wrinkle resistance of cotton and other cellulosic fabrics without at the same time creating unacceptable changes in other desired characteristics of the fabric.

Further objects include the provision of:

(1) New and improved cellulose reacting compositions that are effective in rendering cotton, linen, viscose rayon, acetate rayon and like textile fabrics highly wrinkle resistant in a wet state and at the same time produce dry wrinkle resistance while retaining good fabric characteristics and properties.

(2) New compositions which comprise water-soluble compounds which can be readily applied to fibrous materials with conventional treating techniques to impart wet and dry crease-resistance to the textile fabrics without high strength losses.

(3) Improvements in the use of water-soluble cellulose cross-linking agents to impart to cellulose fabrics wet and dry crease resistance which mitigate loss in tensile strength, toughness index, tear strength and flex abrasion of the treated fabric and detriment to whiteness or color.

(4) New cellulose cross-linking processes that improve uniformity of fiber reaction rendering the treated fabric highly resistant to wet and dry creasing without substantial adverse effects.

(5) Improved cellulose fabrics having good wash-wear qualities and other relatively good properties as compared to untreated fabrics.

(6) New compositions and methods for producing wash-wear cloth for mens shirting, dress goods, childrens apparel, bedding and outer wear.

(7) Wash-wear fabrics of both 100% cotton and cotton-synthetic fiber blends having improved wear life and less dye abrasion or frosting problems than wash-wear fabrics available heretofore.

(8) Improvements in the use of aprotic organic cellulodilators with crease-proofing treatment of cellulosic fabrics that minimize or eliminate color, storage and odor problems.

(9) High wet crease recovery in wash-Wear cellulosic fabrics *with little reduction in abrasion resistance, minimal discoloration and desirable properties as to scorching, particularly with treated white cotton fabric.

(10) Information as to how to obtain an excellent value in abrasion resistance and color improvements in treatment of cellulosic fabric to produce wash-wear garments.

Other objects and further scope of applicability of the present invention will become apparent from the detailed description given hereinafter; it should be understood, however, that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by Way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.

GENERAL DESCRIPTION These objects are accomplished according to the present invention by the treatment of cellulosic fabrics with aqueous solutions of nitrogen-containing, water-soluble, heatcurable organic crease-proofing materials 'which include as an essential ingredient, an aprotic organic cullulodilator.

More particularly, the invention encompasses imparting crease resistance to cellulosic fabrics by:

(A) Impregnating a cellulosic fabric with an aqueous solution which contains:

(a) A Water-soluble, nitrogen-containing, heat-curable organic crease-proofing material of known general classes of cellulose crease-proofing and cross-linking agents and advantageously selected from the group consisting of water-soluble amine-aldehyde reaction products, formaldehyde, alkanol hemiformals, dialdehydes and aziridinyl phosphine oxides,

(b) An aprotic organic cellulodilator capable of opening some hydrogen bonds in the crystalline regions of cellulosic fibers and advantageously selected from the group of such materials as hereinafter delineated, and

(0) An inorganic cellulodilator advantageously selected from the group of materials as hereinafter delineated,

(B) Drying the impregnated fabric to leave a residue in the fabric of the water-soluble crease-proofing material and the cellulodilator mixture, and

(C) Heating the dried fabric to an elevated temperature suflicient to heat-cure the impregnated material and create crease-resistance in the fabric. The treatment is preferably carried out under acid conditions, i.e., a pH between about 17 and especially a pH between about 26, in the presence of an acidic aminoplast forming catalyst.

Advantageously, the new treating compositions are Water solutions containing between about 1 to by weight of an organic crease-proofing agent, 1 to by weight of cellulodilator and 1 to 10% by weight of a curing catalyst for the crease-proofing agent. Such solutions are applied to the fabric by padding or comparable impregnating methods to give a pickup of about 50 to by weight of such aqueous solutions. The mixtures of the two or more cellulodilators produce, particularly in preferred combinations, synergistic effects.

Following the application of the aqueous treating solution, the impregnated or otherwise treated fabric or fiber substrate is dried and then heated to a temperature to effect curing of the impregnated fabric. Typical drying conditions involve heating to a temperature of 100 to 150 C. for between 1 to 60 minutes and typical curing conditions involve heating to 100 to 200 C. for l to 60 minutes following drying. After the curing operation, the treated fabrics are preferably scoured to remove unreactive materials and dried, advantageously with di mension control to fix the final shape and dimensions of the treated dried fabric.

The term cellulodilator as used herein means a compound which is capable of dilating or swelling cellulose to a greater extent than water at temperatures between and 100 C. and which, in addition, fulfills the following requirements:

(a) Does not interfere with the curing of the cellulose crease-proofing agent, react with such agent or poison the curing catalyst,

(b) Is water-soluble, i.e., at least one or more parts will dissolve in each 100 parts of water at C.,

(c) Is relatively non-volatile at temperatures between 100-200 C.,

(d) Does not decompose cellulose or degrade the fibers under conditions of use,

(e) Does not appreciably discolor cellulose under conditions of use, and

(f) Is capable of generating increased penetration of cellulose fiber by the crease-proofing agents as compared to penetration in its absence.

The term aprotic as used herein means that the compound neither accepts nor donates a proton.

EXAMPLES A more complete understanding of the new methods, compositions and improved cellulosic fabrics of this invention may be had by reference to the following detailed examples of operations conducted in accordance with the invention. In these examples and throughout the remainder of the specification and claims, all parts and percentages are by weight unless otherwise specified.

EXAMPLE 1 Samples of plain weave cotton print cloth lwere impregnated by total immersion in the test solution at 20 C. followed by mangling to give about 80% wet pickup, then framed to the original dimensions, dried in a hot air oven for 5 minutes at 120 C., and cured in a second hot air oven for 5 minutes at 120 C. The fabric samples were washed in an automatic home washer to remove unreacted materials and redried on frames for 5 minutes at 120 C. The different test solutions used were:

SOLUTION 1 Percent Dimethylol ethylene urea 2 Hydrated zinc nitrate 1 SOLUTION 1A Dimethylol ethylene urea 2 Hydrated zinc nitrate 1 Dimethyl sulfoxide 10 SOLUTION 2 Dimethylol ethylene urea 4 Hydrated zinc nitrate 1 SOLUTION 2A Dimethylol ethylene urea 4 Hydrated zinc nitrate 1 Dimethyl sulfoxide 10 6 SOLUTION 3 Dimethylol ethylene urea 6 Hydrated zinc nitrate 1 SOLUTION 3A Dimethylol ethylene urea 6 Hydrated zinc nitrate 1 Dimethyl sulfoxide l0 SOLUTION 4 Dimethylol ethylene urea 8 Hydrated Zine nitrate 1 SOLUTION 4A Dimethylol ethylene urea 8 Hydrated zinc nitrate 1 Dimethyl sulfoxide 10 SOLUTION 5 Dimethylol ethylene urea l0 Hydrated zinc nitrate l SOLUTION 5A Dimethylol ethylene urea 10 Hydrated zinc nitrate 1 Dimethyl sulfoxide 10 EXAMPLE 2 The comparative effects of various aprotic organic cellulodilators on the physical properties of an x '80 white cotton print cloth treated with an aqueous solution in water of 5% dimethylol ethylene urea, 1% hydrated zinc nitrate and varied amounts of the cellulodilator is reported in the following table:

TABLE I Treating bath additive MC RA Cone, Tensile percent Composition Wet Dry strength DMSO, dimethyl sulfoxide; DMF, dimethyl formamide; DMAc, dimethyl acetamide; LiTC, lithium thioeyanate; NMP, N-methyl pyrrolidone.

EXAMPLE 3 White cotton twill fabrics were impregnated with a delayed cure durable press finishing solution containing 10% of 1,3-dimethylol-4,S-dihydroxy ethylene urea, 1% Zn(NO -6H O catalyst, padded and dried 5 minutes at 220 F. Then they were cured for 5 minutes at 320 F. Similar treatments were made wherein the above solution were included various inorganic cellulodilators in synergistic mixtures. The results of tests made on the treated fabrics are shown below.

Wrinkle resistance Cured Surface fabric Cellulodilator in finishing solution Dry Wet abrasion color N one-control 260 255 860 3 5% DMSO 255 265 1, 780 1 5% DMSO plus 5% Al(OH) Ol 270 260 3, 250 0 5% DMSO plus 5% Zr(OH)aCl 269 280 3,110 0 5% DMSO plus 5% MgClz-6HzO 270 269 2, 700 0 5% DMSO plus 5% CaClz 265 259 2, 890 0 When the cured wrinkle resistant fabrics were further ironed at 365 F. for one minute, those which contained the mixed organic-inorganic cellulodilators remained white. The control sample turned brown. The DMSO containing sample was yellow. Since most commercial durable press resins are crude reaction products, the value 8 minutes at 160 C. and aging for 20 hours at 50 C. The treated fabric was laundered using a standard automatic washer with 15 grams commercial detergent at cotton setting with 60 C. water temperature and then dried on frames for 5 minutes at 120 C.

The results are reported in the table:

TABLE II MCRA Abrasion Formulations Dry Wet Stoll WyZeub. Color Odor No additive 272 269 170 1, 553 1 Acid. With 5% DMSO 265 358 1, 308 3 DMSO. With 10% DlWISO 266 255 2, 020 4 DMSO. 5% MgCh 239 271 300 931 Acid. MgClz plus 5% DMSO 270 274 334 1, 088 1 None. 5% MgClg plus DMSO. 273 282 380 846 0 DMSO. 10% MgClg 265 273 593 1, 746 1 Acid. 10% MgClz plus 5% DMSO 275 277 533 1, 393 1 None. 10% MgClg plus 10% DMSO 282 291 521 l, 277 2 DMSO. 5% CaClg 205 228 773 1, 678 0 5% (321012 plus 5% DMSO 216 245 691 2, 246 0 5% 023.012 plus 10% DMSO 207 240 040 2, 044 1 10% CaClg 105 221 000 2, 224 0 10% CaClz plus 5% DMSO 222 241 856 2, 588 0 10% CaClg plus 10% DMSO 221 253 812 2, 479 0 Zirconium chlorhydroxide-Zr(0H),,Cl Aluminum chlorhydroxideAl OH) Cl Magnesium chloride-MgCl Calcium chlorideCaCl In the foregoing table, the column headed Color reports the discoloration values after curing of the sample on a scale of 0-5 as described hereinafter.

EXAMPLE 5 Bleached, mercerized 136 x 68 combed 2.85 broadcloth, 100% cotton was treated using the general procedure described in Example 4 with a 20% solution of the Permafresh 183 crease-proofing agent and various cellulodilators and catalysts as reported in the followin Table III:

TABLE III MCRA Stoll Tensile, Formulation Dry Wet abrasion lbs. Color Run N o.:

1 4% Catalyst X- i w 267 180 85 3 2 5% DMSO plus 5% MgClz. 01120 264 267 416 86 2 3. 10% DMSO plus 10% ZnClz 231 288 362 83 4 4. 5% DMSO plus 5% Alz(OH)5C]. 2HzO 251 230 383 107 0 5. 10% DMSO plus 10% Al2(OH)5Ol. 2Hz0 260 272 438 78 0 6 5% DMSO plus 5% ZI(OH)2C12 214 231 520 108 0 7 10% DMSO plus 10% Zr(OH)zClz 256 275 403 78 0 8 Untreated control 125 148 612 158 0 are effective with a larger number of crease-proofing resins and reactants than DMSO alone; they eliminate the yellowing of fabrics produced by commercial glyoxal based durable press resins; and they produce even better fabric strength-wrinkle recovery relationship.

EXAMPLE 4 A series of fabric treatments were conducted on bleached mercerized combed 160, 100% cotton twill fabric using commercially available crease-proofing materials Permafresh 183 with Catalyst X4 in the presence of dimethyl sulfoxide as an aprotic organic cellulodilator and several inorganic metal salts. The Permafresh 183 cross-linking agent is polymethylol dihydroxy imidazolidone and the X4 is principally zinc nitrate catalyst.

The basic treating composition was an aqueous solu tion of 25% Permafresh 183, 4.5% catalyst X-4 and 0.1% nonyl phenyl polyethylene glycol ether (Wetting agent). To this basic solution was added various amounts of dimethyl sulfoxide and inorganic metal salts as reported below in Table II.

The procedure followed was to pad onto the fabric 78% of the treating solution with a 2 dip, 2 nip padding operation in standard padding apparatus. The padded fabric was then dried for 5 minutes at 105 C., pressing for seconds With a damp cloth and hot iron, curing for 10 TEST VALUES The physical tests employed to evaluate the efiects produced in the treated fabrics in the above examples are as follows: All values reported are the average of five replicate tests.

MCRAMonsanto Crease Recovery Angle in degreestotal Warp plus filling unless specified otherwise. Fed. Spec. CCCT-191b., Method 5212.

Note: Wet MCRA values are obtained by soaking the test specimen in distilled water with 0.1% wetting agent at room temperature for 1 hour, blotting with blotting paper and testing as above.

test method Discoloration-Visual determination on arbitrary scale of 0.5 using control comparison samples, namely: white; 1very light yellow; 2light yellow; 3deep yellow; 4dark yellow and 5brown.

Odor Evaluation-After padding the solutions were put in jars and those sealed and stored overnight at 22 C. The padded and dried fabrics were sprinkled with distilled water, rolled on a glass rod, put in polyethylene bags and sealed, then placed in oven at 40 C. for 30 minutes, and finally put overnight in conditioning room. Odor test was performed by three dilferent operators.

DISCUSSION OF DETAILS The treating compositions used in carrying out the crease resistant improving procedures of this invention are aqueous solutions containing two essential ingredients, namely, (a) water-soluble, heat-curable nitrogen-containing organic material known to possess crease-proofing properties when used in the treatment of cellulosic fabrics, and (b) the cellulodilators. The invention is preferably conducted using water-soluble amine-aldehyde reaction products known to be useful in the crease-proofing of cotton or other cellulosic fabrics. However, the invention is contemplated for use with any other form of nitrogencontaining, water-soluble organic materials now known to be useful for crease-proofing of cellulosic fabrics or found in the future to be useful for this purpose, e.g., Water-soluble alkylated amine-aldehyde reaction products, aziridinyl phosphine oxides or comparable materials.

Specific examples of nitrogen-containing, water-soluble, heat-curable organic cellulose fabric crease-proofing materials which may advantageously be used in accordance with the invention include:

From the class of amino-aldehyde reaction products, the monomers and water-soluble polymers of:

dimethylol urea trimethylol melamines dimethylol ethylene urea polymethylol melamine polymethylol alkyl carbamates polyalkylated monoureins (see US. 3,209,010)

N,N-dimethylol or dialkoxymethyl monoheterocyclic ureas represented by the following generic structure:

where X is: C=O, C=NH, or C=S and R is: H or a lower alkyl and Y is: a divalent alkylene or substituted alkylene radical, as for example:

From the class of alkylated amino-aldehyde reaction products, the monomers and water-soluble polymers of:

dimethoxymethyl urea trimethoxymethyl melamine.

From the class of aziridinyl phosphine oxides:

tris aziridinyl phosphine oxide tris methyl aziridinyl phosphine oxide.

Various organic and inorganic cellulodilators are known and have been used in various prior processes to dilate cellulose molecules in chemical reactions. This reagent must dilate the cellulosic fibers and keep them dilated during the curing of the crease-proofing agent, even after water has evaporated. It has been found that from this known class of materials, the aprotic organic compounds are unique in the new methods of this invention. Dimethyl sulfoxide is the preferred aprotic organic cellulodilator, but other useable organic cellulodilators include dimethyl formamide, dimethyl acetamide, N-methyl pyrrolidone, 2- pyrrolidone, tetramethyl urea, vinyl pyrrolidone, sodium xylene sulfonate, butyrolactone and dimethyl sulfone.

Lithium thiocyanate is an example of an inorganic cellulodilator. Other inorganic salts higher in the lyotropic series than lithium thiocyanate are also contemplated for use, i.e., water-soluble inorganic salts having greater water of hydration than lithium thiocyanate, e.g., LiBr, CaBr MgCl CaCl zirconium chlorhydroxide and aluminum chlorhydroxide.

The treating compositions used to impart wet and dry crease resistance to cellulosic fabrics in accordance with the invention are aqueous solutions containing dissolved therein the nitrogen-containing organic anti-crease agent, the cellulodilators and, preferably, in addition, an acidic aminoplast forming catalyst. Generally, the solutions will contain 1 to 20% of the nitrogen-containing agent, 1 to 20% cellulodilators and l to 5% of the acidic catalyst.

Specific examples of acidic catalysts which may be used in accelerating the curing of nitrogen-containing compounds and reaction thereof with cellulose in the fabrics include Zinc nitrate, zinc chloride, Zinc fiuoroborate and comparable acid reaction metal salts. In addition, acid reacting salts of ammonia or amines may be used, e.g., ammonium silicofluoride, diammonium acd phosphate, ammonium bisulfate, ethanolamine hydrochloride and the like. Suitable catalysts also include free acids, e.g., hydrochloric, phthalic, tartaric, citric and similar acids.

No special form of equipment is required in carrying out the procedures of the invention. This constitutes an important advantage of the new procedures for it makes possible the easy addition of the operation to established textle finishing and handling plants. Likewise, generally available, commercially used drying, shaping and textile handling equipment may be employed in carrying out the drying, heating and dimension controlling steps of the new operations. Furthermore, the new procedures may be applied in conjunction with other textile processing operations generally considered useful by the textile industry. Such procedures include water-proofing, mildewproofing, calendering, embossing, dyeing, printing and the like. Other known finishing agents not incompatible or detrimental to these new treatments may be applied on conjunction with the crease-proofing agents of this invention, e.g., lubricants, sizing materials, moth-proofing agents, water-proofing agents, brighteners, dyes, pigments and the like. Some or all of these types of materials may be included in the actual treating compositions of this invention in amounts advantageously about 1 to 10%.

The impregnation of the aqueous treating compositions is probably most easily accomplished by standard padding procedures although any other type of solution applicating procedure may be employed, e.g., spraying, brush application, roller coating, transfer from saturated webs or the like. Whatever procedure is employed, the fabric should be impregnated with suflicient of the aqueous composition so that when the fabric is completely dried, there will remain in the fabric as the non-volatile residue, between about 1 and 20% of the nitrogen-containing, creaseproofing agent, and advantageously, 3 to 10% by weight of the crease-proofing agent. With the preferred aqueous compositions, this can readily be accomplished by adjusting the impregnation to give a pickup of 50 to by weight based upon the dried weight of the fabric or other fiber substrate to which the solution is applied.

Solution composition and fabric pickup is preferably controlled to place in the fabric before the curing step a nitrogen-containing, crease-proofing agent to cellulodilator 1 1 weight ratio of between about 10:1 and 3:20, and a weight ratio of the curing agent to curing catalyst of between about 5:3 and 1:20. With the cellulodilator mixture, the ratio of the aprotic organic cellulodilator to inorganic cellulodilator may be varied and advantageously is between 5:1 and 1:5 and particularly between 4:1 and 1:2.

The aqueous solution impregnated fabrics or other fibrous webs are dried, preparatory to the heat curing step. This can be accomplished by air drying at room temperature using forced air circulation or, preferably, by heating such as with radiant or convection heat in ovens, tunnels or the like to an elevated temperature between about 50 and 100 C. and especially 100 to 150 C. for between about 1 to 60 minutes. The drying step need not be conducted any longer than necessary to effect substantial complete drying and generally shorter times will be required for higher temperatures.

After the substrate is dried, it is subjected to an elevated heating step in order to effect a curing which appears to involve a condensation of the solid residue materials in the fabric with themselves and with the cellulose. The heat curing is advantageously conducted at a temperature above 100 C. and below the decomposition temperature of the fabric, preferably between 100 and 200 C. and usually for between about 1 to 60 minutes, longer times generally being employed at the lower temperatures and vice versa. Drying and curing can take place at the same temperature if this is above about 100 C. and in the same oven or dryer if desired.

Following the heat curing step, it is advantageous to wash or scour the fabric in order to remove unreacted material. During this stage of the operation, it may be found desirable to treat the fabric with softening agents, sizing agents, lubricants or the like. Following this cleansing, the fabric is dried, preferably using some type of dimension control such as tenters or other dimension control frames or equipment to ensure even drying and squaring of the fabric.

The new crease-proofing operations are particularly useful for the finishing of cotton fabric which will be used for wearing apparel, such as mens shirts, womens dresses, childrens clothing or the like, yard goods, sheeting and similar household fabric. However, the operations are also useful with any other form of fabric including non-woven as well as woven webs, knitted goods and the like composed of fibers of cellulosic origin, e.g., cotton, viscose rayon, acetate rayon, linen and the like. Cloth or other fibrous webs composed partially of fibers of cellulosic origin and partially of other natural or synthetic fibers may also be treated, e.g., Webs, containing in part, wool, silk, nylon, acrylic fibers, modacrylic fibers, polyester fibers and the like.

CONCLUSION The invention described above provides new improvements in the general art of treating fabrics with nitrogencontaining, crease-proofing agents in order to render the fabrics anti-creasing and resistant to wrinkling. In a more popular sense, the described invention provides improvements in the manufacture of wash and wear cotton and other cellulosic textiles. The invention is characterized by the use of a cellulodilator as defined as a critical ingredient along with conventional nitrogen-containing organic crease-proofing agents and is dependent upon the discovery that such use of dimethyl sulfoxide or equivalent cellulodilator produces a critical improvement, as compared with prior known operations, in strength and other desirable properties of the treated fabric for the same level of wet and dry crease resistance. Notably, the tensile strength to crease resistance, tear strength to crease resistance and flex abrasion to crease resistant ratios of the treated fabrics are substantially increased as compared with prior art procedures.

Without any intent to limit the scope of the invention, but in explanation of the unique results which are obtained by the Omniset Process, the success of the invention appears to result from fiber dilation created by the cellulodilator. Cellulose fibers comprise a polymeric network of both crystalline and amorphous regions. The crystalline regions are not readily accessible to water or to aqueous solutions of treating agents because of the strong hydrogen bonding of the hydroxyl group from neighboring molecules. The amorphous or less dense regions are the areas wherein dyes, crease-proofing agents, water, etc., may penetrate. In cotton, there are about by weight of crystalline regions and about 15% amorphous regions (depending on methods of measurement). The amorphous regions, however, are the part of the cellulose structure which give the fiber flexibility, extensibility and contribute to toughness. When cotton is treated with crease-proofing agents, i.e., cross-linking agents, aminoplasts, thermoesetting resins, etc., apparently the amosphous regions become very rigid and lead to a brittle fiber structure since all of the cross-linking agent is concentrated in one area of the polymer network. The present invention involves the concept of dilating the cellulose molecular aggregation so that crease-proofing agents can penetrate into previously inaccessible regions of the fiber so as to lead to a more even distribution of cross-linking agent in the fiber and to better retention of tensile strength, tear strength and abrasion resistance in crease-proofed fabrics.

The embodiments of the invention in which an exclusive property or right is claimed are defined as follows:

1. In a method for the treatment of a cellulosic fabric with an aqueous solution of an organic, water-soluble nitrogen-containing cellulose crease-proofing material to improve crease-resistance of the fabric, the step of using in said solution an aprotic organic cellulodilator as a means to increase the tensile strength to wet crease recovery value ratio of the treated fabric, said cellulodilator being an organic compound that is relatively non-volatile at temperatures between to 200 C. and capable of swelling cellulose to a greater extent than water at temperatures between 10 and 100 C.

2. A method as claimed in claim 1 wherein said aprotic organic cellulodilator is selected from the grou consisting of dimethyl sulfoxide, dimethyl formamide, dimethyl acetamide, N-methyl pyrrolidone, 2-pyrrolidone, tetramethyl urea, vinyl pyrrolidone, butyrolactone and dimethyl sulfone.

3. In a method for the treatment of a cellulosic fabric with an aqueous solution of an organic, water-soluble, nitrogen-containing cellulose crease-proofing material to improve crease-resistance of the fabric, the step of using in said solution a combination of an aprotic organic cellulodilator and an inorganic cellulodilator as a means to increase the tensile strength to wet crease recovery value ratio of the treated fabric, said cellulodilators being compounds that are relatively non-volatile at temperatures between 100 to 200 C. and capable of swelling cellulose to a greater extent than water at temperatures between 10 and 100 C.

4. A method as claimed in claim 3 wherein:

(a) the weight ratio of said crease-proofing material to cellulodilator in the aqueous solution used in the treatment of the cellulosic fabric is between about 10:1 and 3:20 and (b) the solution contains between about 1 to 20 percent of said combination of cellulodilators.

5. A process as claimed in claim 3 wherein said solution contains an aprotic organic cellulodilator selected from the group consisting of dimethyl sulfoxide, dimethyl formamide, dimethyl acetamide and N-methyl pyrrolidone, 2-pyrrolidone, tetramethyl urea, vinyl pyrrolidone, butyrolactone and dimethyl sulfone, and an inorganic cellulodilator selected from the group consisting of lithiurn thiocyanate, lithium bromide, calcium bromide, magnesium chloride, calcium chloride, zirconium chlorhydroxide and aluminum chlorhydroxide.

6. In the treatment of cellulosic fabric with aqueous solutions of nitrogen-containing organic compounds to improve crease-resistance of the fabric, the step of using in said solution dimethyl sulfoxide as an agent to increase the tensile strength to wet crease recovery value ratio of the treated fabric.

7. A process for improving the wash and wear qualities of cellulosic fabric while retaining in the fabric good tensile strength, tear strength and flex abrasion resistance which comprises:

(A) impregnating fabric formed at least in part of cotton fibers with 50150 percent, based upon the dry weight of the fabric, of an aqueous solution containing:

' (a) 1-20 percent of aminoaldehyde crease-proofing agent,

(b) 1-5 percent acidic catalyst,

(c) an aprotic organic cellulodilator that is relatively non-volatile at temperatures between 100 to 200 C. and capable of swelling cellulose to a greater extent than water at temperatures between and 100 C., and

(d) an inorganic cellulodilator being a compound different from said acidic catalyst that is relatively non-volatile at temperatures between 100 to 200 C. and capable of swelling cellulose to a greater extent than water at temperatures between 10 and 100 C., the amounts of components (c) and (d) in said solution being about equal and the total combined weight of (c) and (d) being about 1-20 percent by weight of said solution;

(B) drying the impregnated fabric to eliminate water from the fibers and to leave a residue in the fabric of the components (a), (b), (c) and (d) of step (A), and

(C) heating the dried fabric to an elevated temperature sufiicient to create crease resistance in the fabric by reaction at said elevated temperature of said crease-proofing agent.

8. A process for imparting improved crease resistance to cellulosic fabrics which comprises:

(A) impregnating a cellulosic fabric with an aqueous solution comprising:

(a) a water-soluble, nitrogen-containing, organic crease-proofing material selected from the group consisting of: water-soluble amine-aldehyde reaction products, water-soluble alkylated aminealdehyde reaction products, aziridinyl phosphine oxides,

(b) dimethyl sulfoxide,

(B) drying the impregnated fabric to leave as residue in the fabric the components (a) and (b) of p (A),

(C) heating the dried fabric to an elevated temperature suflicient to create improved crease resistance in the fabric.

9. A cellulosic fabric having an improved ratio of tensile strength to Wet crease recovery containing the heat-cured reaction product of cellulose fibers in the fabric with 3 to 10 percent by weight based upon the dry weight of the fabric of amino-aldehyde crease-proofing agent in the presence of a mixture of an aprotic organic cellulodilator and an inorganic cellulodilator produced by treatment of the cellulosic fabric with an aqueous solution containing an amino-aldehyde crease-proofing agent, an aprotic organic cellulodilator and an inorganic cellulodilator, said cellulodilators being compounds that are relatively non-volatile at temperatures between to 200 C. and capable of swelling cellulose to a greater extent than water at temperatures between 10 and 100 C., the weight ratio of said crease-proofing agent to said mixture of cellulodilators being between about 1:10 and 20:3, said treatment comprising impregnating the cellulosic fabric with said aqueous solution, drying the impregnated fabric to eliminate water from the fibers and leave a residue in the fabric of the crease-proofing agent and cellulodilators and heating the dried fabric to an elevated temperature sufficient to create improved crease resistance in the fabric by reaction at said elevated temperature of said crease-proofing material.

10. A cellulosic fabric having an improved ratio of tensile strength to wet crease recovery containing the heat-cured reaction product of cellulose fibers in the fabric with 3 to 10 percent by weight based upon the dry weight of the fabric of polymethylol cyclic urea in the presence of a mixture of an aprotic organic cellulodilator selected from the group consisting of dimethyl sulfoxide, dimethyl formamide, dimethyl acetamide, N- methyl pyrrolidone, 2-pyrrolidone, tetramethyl urea, vinyl pyrrolidone, butyrolactone and dimethyl sulfone and an inorganic cellulodilator selected from the group consisting of lithium thiocyanate, lithium bromide, calcium bromide, magnesium chloride, calcium chloride, zirconium chlorhydroxide and aluminum chlorhydroxide, the weight ratio of said cyclic urea to said mixture of cellulodilators being between about 1:10 and 20:3, said treatment comprising impregnating the cellulosic fabric with said aqueous solution, drying the impregnated fabric to eliminate water from the fibers and leave a residue in the fabric of said cyclic urea and cellulodilators, and heating the dried fabric to an elevated temperature sufficient to create improved crease resistance in the fabric by reaction at said elevated temperature of said cyclic urea.

References Cited UNITED STATES PATENTS 2,679,449 5/ 1954 Schappel 8116.4 2,926,063 2/ 1960 Reeves et a1. 8116.2 3,007,763 11/1961 Adams 81162 3,043,719 7/1962 Burr et a1. 8116.3 3,046,079 7/ 1962 Reeves et al. 8116.4 3,061,399 10/1962 Tesoro et a1. 8120 3,128,222 4/1964 Herschler et a1. 8116.3 X 3,181,927 5/1965 Roth et a1. 8116.3

OTHER REFERENCES Gagliardi et al.: Textile Research Journal, vol. 31, pp. 316-317 (1961).

Volko et al.: Textile Research Journal, vol. 32, pp. 331-337 (1962).

GEORGE F. LESMES, Primary Examiner JAMES CANNON, Assistant Examiner US. Cl. X.R. 

